The Taxpayer Rights Protection Act Article 9

Interpretative letters or directives and other administrative rules about tax matters made by the tax authorities shall be made public, unless they involve official secrets, business secrets, or personal privacy.Interpretative letters or directives which are not made public according to Paragraph 2 of Article 160 of the Administrative Procedure Act, Article 8 of the Freedom of Government Information Law, or other appropriate means shall not be relied upon in other cases.The central competent authority shall review every four years whether or not the interpretative letters or directives violate the provisions or spirits of any statute, or create or increase any obligation to pay tax without statutory basis, and may entrust such tasks to external research institutions.